[2] Class 1-Lipids-Agbas Flashcards
What is water insoluble but highly soluble in organic solvents?
Lipids
What is the key constituent of Lipids?
Fatty acids
What part of the lipid is responsible for hydrophobic properties?
Fatty acids
What makes lipids amphipathic?
Hydrophobic fatty acid tail
Hydrophilic phosphate head group
Unsaturated double bond in FA tail contributes 2 things:
Allows cholesterol to be in between 2 FA’s and provides fluidity to the membrane
Proteins are modified by what attachment that allows them to target membranes
Covalent attachment of FA’s
Functions of FA’s:
Membrane component
Store fuel as triacylglycerols (TAG)
Derivatives serve as hormones, signal molecules, and Intracellular messengers
How do you number carbons in FA chain?
Starting at carboxyl terminus
OR
Omega begin counting at methyl carbon at distal end of the chain
Carbons 2 and 3 of fatty acid
alpha and beta
How to name fatty acids?
E changes to -oic.
Double bonds change
-ane to en to dien to trien
18:0
Vs
18:2
18 Carbon FA w/ no double bonds and :2= 2 double bonds
Fatty acids usually contain an _____ number of Carbon atoms, typically between ____ and ____ carbons
EVEN ; 14 and 24
What length FA’s are most common?
16- and 18-
Configuration of the double bonds in most unsaturated FA’s is
Cis
FA’s are _______ at physiological pH
Ionized
What determines the properties of fatty acids?
Length of hydrocarbon chain
Degree of saturation
Relate melting point and unsaturated FA vs. saturated FA
Unsaturated has lower melting point…doesn’t allow for tight packing
How is melting point affected when saturated FA increase w/ chain length?
M.P increases w/ increased chain length d/t more tight packing is possible w/ more carbon groups
Name the 3 essential FA’s:
Linoleate
Linolenate
Arachidonate
Which EFA is not really a EFA?
Arachidonate
Can be manufactured by linolenate
What type of bond is found in archea that allows life in extreme environments? Why?
Ether bonds; they’re more resistant to hydrolysis
They also have branched and saturated hydrocarbons- resistant to oxidation
3 major membrane lipids:
Phospholipids
Glycolipids
Cholesterol
2 types of phospholipids
Phosphoglyceride
Sphingomyelin
Major glycolipid:
Cerebroside
What are the 4 components of a phospholipid?
1 FA
2 A backbone
3 A phosphate
4 An alcohol
Which properties allow phospholipids to interact w/ the environment?
Hydrophilic properties of the phosphate and alcohol groups.
Name the simplest phosphoglyceride:
Phosphatidate
OR
Diacylglycerol 3-phosphate
What process is Phosphatidate or diacylglycerol 3-phosphate involved in?
It is a key intermediate in the biosynthesis of other phosphoglycerides
Is there a lot of Phosphatidate in membrane?
No only small amounts of phosphatidate are present in membranes
What is derived from Phosphatidate?
Phosphoglycerides
Phosphoglyceride important for memory and cognition
Phosphatidylserine
Phosphoglyceride that it’s major constituent of cell membrane and pulmonary surfactant
Phosphatidylcholine
Phosphoglyceride composing 25% of all phospholipids and are found, particularly in humans, in nervous tissue such as the white matter of the brain
Phosphatidylethanolamine
Phosphoglyceride important for signaling and other functional activities in eukaryotic cell
Phosphatidylinositol
Phosphoglyceride that is important component of inner mitochondrial membrane
Diphosphatidylglycerol
Amino group replaces a fatty acid component of phosphoglyceride…other fatty acid is unsaturated c-18
Amino Alcohol
Sphingosine
Sphingosine + FA
Ceramide
Ceramide + phosphorylcholine
Sphingomyelin
Ceramide + monosaccharides
Cerebrosides
Ceramide + oligosaccharides
Globoosides
Ceramide oligosaccharides + NANA
Gangliosides
Phospholipid w/ sphingosine as backbone w/ amide bonded FA and phosphorylcholine group
Sphingomyelin
Where is sphingomyelin found? And what purpose does it serve?
Animal cell membranes in myelin sheath that surrounds some nerve cell axons
It provides electrical insulation for nerve transmission
- Sugar-containing lipids
- Derived from sphingosine
- Differ from sphingosine d/t unit linked to OH- grp of backbone
Glycolipids
Glycolipids sugar moiety face intra/extracellular?
Extracellular. It is involved in cell to cell interactions
- The simplest glycolipid
- Contains single sugar residue
- Also called monoglycosylceramides
Cerebrosides
Function of Cerebrosides:
Important components in animal muscle and nerve cell membranes
A steroid, present in eukaryotes [not most porkaryotes]
Built from 4 fused saturated hydrocarbon rings
Classified as sterol b/c of OH- grp. And branched aliphatic side chain o 8-10 C atoms at C-17.
Cholesterol
Which Carbon has the OH-grp in cholesterol?
Carbon 3
Scientific name of cholesterol
Cyclopentanoperhydrophenanthrene ring system
Most abundant steroid in animals
Major component of eukaryotic plasma membrane
Cholesterol
Cholesterol orientation in membrane?
Parallel to FA chains of the phospholipids, and the hydroxyl group interacts w/ the nearby phospholipid head group.
Cholesterol is absent in:
Some Intracellular membranes
And
Prokaryotes
Metabolic precursor of steroid hormones:
Cholesterol
Key components of lipids:
FA’s
